Snowflakes/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby A robot, Moby, is standing in snow, looking up at the sky through a magnifying glass. He is bent over backwards. A boy, Tim, comes over to him. TIM: That looks really uncomfortable. What are you… what are you doing? MOBY: Beep. TIM: Well, okay, just be careful not to fall. Moby falls back into the snow. MOBY: Beep. TIM: You okay there? Tim reads from a typed letter. TIM: Dear Tim and Moby, how do snowflakes form? And are they really all different? From, Lars. Tim looks up at the sky. TIM: Uh, let's take a look at where they form. Snowflakes are actually made up of snow crystals, or ice crystals, that form inside clouds. An animation shows hexagon-shaped ice crystals falling. TIM: At extremely cold temperatures, like less than minus forty degrees Celsius, the water vapor inside clouds can condense directly into ice. At temperatures between zero degrees Celsius and minus forty degrees Celsius, water vapor first condenses onto dust particles making little droplets that freeze. An animation shows a cloud and a thermometer that reads negative 40 degrees Celsius. The cloud forms into an ice crystal. The thermometer now reads between negative 40 degrees Celsius and 0 degrees Celsius. A dust particle freezes into a crystal as Tim describes. MOBY: Beep? TIM: Ah, well, I'm getting to that. Everyone knows that the molecular name for water is H2O. That means that one water molecule is made up of two hydrogen atoms bonded with one oxygen atom: H2O. An image shows a glass with H2O written on it. A call-out shows the structure of a water molecule: One water molecule equals 2 hydrogen atoms and 1 oxygen atom. TIM: In liquid form, water molecules bump up against each other and move all around. Though when water freezes, the molecules arrange themselves into a more stable formation: the crystal lattice. An animation shows oxygen and hydrogen atoms in water floating around and colliding. Then it shows the atoms linking together in a lattice pattern. MOBY: Beep. TIM: The ice crystals that make up snowflakes are symmetrical because they reflect that internal order of the water molecules. Side by side images show a hexagon-shaped ice crystal and molecules in a lattice formation. MOBY: Beep. TIM: Yeah, the crystal lattice is the basis for every snow crystal and snowflake out there. An animation shows the hexagon-shaped crystals coming together in lattice patterns. They form different shapes depending on how the hexagons are arranged. TIM: A snowflake's shape is determined by the conditions under which it forms. An image shows a variety of different shaped snowflakes. TIM: Mostly we're talking about the temperature and the humidity of the air. Side by side images show a thermometer and a drop of water. TIM:The colder the air temperature, the sharper the tips of the crystal will be. At warmer temperatures, ice crystals grow slower, making for more subtle shapes. Crystals are shown that formed in colder and warmer temperatures. An arrow shows that the top crystal was formed in colder air temperatures than the one on the bottom. The crystal on top is sharper with a more complex shape than the more rounded and less defined crystal on the bottom. TIM: Snow crystals tend to form simpler shapes when humidity is low and more complex shapes when it's high. An arrow indicates a range of humidity from dryer to damper. Above the arrow, three crystals illustrate simple, complex, and very complex shapes. The simplest shape is formed when there’s less humidity and the most complex shape is formed when there is high humidity. MOBY: Beep. TIM: Well, those are the snow crystals in their purest structure. They stick together to form our snowflakes. And they continue to grow and change as they fall towards earth. By the time a snowflake reaches the earth's surface, plenty of elements have affected its shape An animation shows crystals sticking together to form different kinds of snowflakes. One snowflake is shown changing as it falls from the sky to the ground. Parts of it fall off after hitting objects on its way down. TIM: Hey, not bad. A snowflake falls on Moby's magnifying glass as he leans back with his head supported by a twig. MOBY: Beep. TIM: Anyway, it's pretty darn unlikely that any two snowflakes could ever look the same. They all form uniquely and have unique journeys, even though they start out with the same molecular structure. An animation shows more snowflakes falling from the sky. Then the crystal lattice diagram appears next to them. TIM: I'm sure Moby can tell us more. Moby is lying under a pile of snow, covering him and the magnifying glass. TIM: What are you seeing, Moby? Category:BrainPOP Transcripts Category:BrainPOP Science Transcripts